1. Field of the Invention
This invention relates to an apparatus for cleaning tubs which contain liquid under operating conditions, which is preferably used, in particular, for washer chambers of an aeration plant but also for water containers in cooling towers or cooling water reservoirs in an air conditioning plant where a constant supply of liquid exists.
2. Description of Prior Art
During operation of washer chambers of, in particular, an aeration plant, deposits settle on bases of the tubs in which a certain level of liquid is continuously maintained and thus lead to silting of the respective liquid, generally water. Chemicals are added, for example to prevent lime deposits and growth of algae, but the chemicals are only effective for a short period and also result in dead algae. Such plant therefore must be shut down and cleaned from time to time with or without chemicals, generally by hand. This is carried out at least every fortnight with washer chambers of humidifiers or with water containers of cooling towers.
Great Britain Patent Reference GB 1 459 853 discloses an automatic cleaner for swimming pools wherein a suction device which can be moved by a drive communicating with a delivery pipe is arranged on the base of the tub, and the drive is operated by a pressure fluid and drives a water wheel which is non-positively coupled to a displacement means contacting the base of the tub and with a filter unit which is connected to a suction pipe. The base of the swimming pool has to be at such an inclination that the suction device equipped with three wheels cannot be overturned as it moves. The suction device also comprises a collecting bag for aspirated components, which constantly has to be opened periodically.
German Patent Reference DE-C2-31 51 529 discloses an apparatus for removing sediment from a precipitation tank in which sediment from a liquid to be clarified settles during operation. A dirt collecting device can be submerged in the liquid. A switching device has a first part capable of moving with respect to a second part, with a device for alternately stopping the movement of each of the two parts with respect to the container. The unstopped part can be moved with respect to the container and with respect to the stopped part. A driving device moves the unstopped part with respect to the other part, wherein the dirt collecting device can be moved over the container base during operation. The switching device can be submerged in the liquid in the vicinity of the sediment deposited therein and the dirt collecting device is arranged on the switching device. The stopping device has a clamping device actuable by liquid pressure, a diaphragm possessing an inlet for the supply and discharge of liquid for expansion and compression of the diaphragm, and a clamping plate which can be moved during expansion of the diaphragm into a position in which its movement and movement of the associated part is stationary with respect to the container.